Synthetic polymeric materials, such as polypropylene and polypropylene comprising a rubber component (e.g., thermoplastic elastomer), are widely used in injection molding manufacturing of a variety of commercial end-uses including articles for automobiles or automobile parts, such as an interior material structure or article. While articles constructed from synthetic polymeric materials have widespread utility, these materials tend to degrade slowly, if at all, in a natural environment. In response to environmental concerns, interest in the production and utility of more readily biodegradable polymeric materials comprising polylactic acid, a biodegradable polymer, has been increasing. These materials, also known as “green materials”, may undergo accelerated degradation in a natural environment.
However, the utility of these “green materials” is often limited by their poor mechanical and/or physical properties. In particular, polylactic acid is known to be brittle and exhibit low toughness, which results in unsatisfactorily low impact strength articles. Blends of polylactic acid with elastomeric materials or other impact modifying polymers have been proposed, however due to poor processability and/or undesirable mechanical properties, previous blends have not been used successfully in automotive part applications requiring impact strength and production efficiency. Therefore, a need exists for a biodegradable blend suitable for injection molding production of articles having improved impact strength, thus providing an environmentally friendly alternative to synthetic polymeric materials or metal in the fabrication of articles such as automotive parts, for example.